Maleic anhydride copolymers have been previously investigated as scale inhibiting agents in the feed waters to various types of heat exchangers. U.S. Pat. No. 3,650,970 discloses the use of alkali metal or ammonium salts of a polymer formed by esterifying styrene maleic anhydride copolymers with capped polyethylene glycols as calcium sulfate scale inhibitors. U.S. Pat. No. 3,715,307 to Johnson et al. discloses the use of maleic anhydride-vinyl acetate copolymers to reduce maintenance problems associated with the use of water in heat transfer equipment. U.S. Pat. Nos. 3,723,956, 3,617,557, 3,289,734 and 3,775,264 disclose the use of other copolymers as scale inhibitors in various types of heat exchangers.